Samsung Fingerprint Sensor Not Working: Causes and Fixes

Know which sensor your Galaxy has

Samsung uses different kinds of fingerprint sensors, and the fixes depend on which one is in your phone.

If you're not sure which model you have, check Settings › About phone. Under-screen sensors are the ones most affected by screen protectors and screen damage.

1. Your screen protector may be the problem

This is the most common reason a Galaxy fingerprint sensor stops working well. Under-screen sensors have to read through the protector as well as the glass, and many protectors get in the way.

• Air gaps and bubbles are especially bad for ultrasonic sensors. Even a small bubble over the sensor area can stop it reading.
• Thick tempered glass not designed for in-display sensors can block or weaken the signal.
• Scratched or cracked protectors over the sensor area confuse optical sensors.

Look for a protector that says it supports your model's in-display fingerprint sensor. After applying any new protector, delete and re-register your fingerprints. Samsung phones also have a Touch sensitivity option under Settings › Display that can help touches register through a protector.

2. Re-register your fingerprints

Fingerprint data registered months ago, or before a new protector, may not match well any more. Starting fresh often helps more than anything else.

1. Go to Settings › Security and privacy › Biometrics › Fingerprints.
2. Enter your PIN, pattern or password.
3. Delete the fingerprints that aren't working well.
4. Tap Add fingerprint and follow the prompts, pressing firmly and moving your finger slightly between touches so the whole pad is captured, including the edges.
5. Consider registering your most-used finger twice, once as you'd hold the phone in one hand and once on a table.

3. Dry, cold or wet fingers

Ontario winters are hard on fingerprint sensors. Cold, dry skin has less contact with the glass, and optical sensors in particular struggle to read it. Very wet or greasy fingers cause problems too.

• Warm your hands up for a moment before unlocking.
• Use hand cream regularly, but wipe off any excess before pressing the sensor.
• Dry wet fingers before unlocking.
• Re-register prints in winter if your skin changes a lot with the season.

Cuts, blisters and calluses on a fingertip can also stop a match. Registering a second finger gives you a backup.

4. Software checks

• Restart the phone. It clears temporary glitches that affect the biometric service.
• Update the software in Settings › Software update. Samsung updates sometimes improve fingerprint performance.
• Clean the screen over the sensor with a soft cloth.

5. After a screen replacement: re-enrol

If your Galaxy's screen has been replaced, delete and re-register all fingerprints once the repair is done. The sensor now reads through different glass, and old fingerprint data often doesn't match as well.

The replacement screen itself matters too. Under-screen sensors need a screen that's compatible with them, and some lower-grade replacement screens don't work well with in-display fingerprint sensors. Ask about fingerprint support when you get your quote, so you know what to expect. Our Samsung Galaxy repair guide has more on screen options.

6. When the display is the problem

An optical sensor relies on the screen to light your finger. If the area over the sensor has dead pixels, a black spot, green lines or a crack, the sensor may not be able to see your fingerprint at all. Ultrasonic sensors can also struggle when the glass above them is cracked or the display is damaged.

Signs the problem is hardware rather than settings:

• The fingerprint icon doesn't light up or appears in the wrong place
• Your phone says it can't detect the fingerprint sensor, or the option is missing
• The screen is cracked or discoloured over the sensor area
• Re-registering fails part way through, every time

When to call a technician

If you've changed the protector, re-registered your prints and updated the phone, and the sensor still won't work, Woman Wireless On The Go can diagnose it at your home or workplace. You'll get a free quote before any work starts, including whether a screen replacement is the likely fix. See our Samsung repair service and our service area, then call or WhatsApp (365) 351-4247.

Frequently asked questions

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